Solar Battery Sizing Guide
Calculate exactly how much battery storage you need for load shedding and overnight power. Don't overpay or under-spec.
Battery is often the most expensive component and the most critical for load shedding backup. Size it wrong and you'll either run out of power or waste money on capacity you don't need.
Calculate Your Backup Needs
Step-by-step calculation:
- 1. List appliances you need during load shedding
- 2. Add up their wattage (check labels or use estimates below)
- 3. Multiply by hours of backup needed
- 4. Add 25% buffer (don't fully discharge lithium)
- Example: 800W × 4 hours × 1.25 = 4kWh needed
Common Appliance Wattage
| appliance | watts |
|---|---|
| LED TV (55") | 80-120W |
| WiFi Router | 10-15W |
| LED Lights (per bulb) | 5-15W |
| Laptop | 50-100W |
| Phone Charging | 10-20W |
| Fridge | 100-200W |
| Microwave | 800-1200W |
| Air Conditioner | 1000-2500W |
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Battery Size Recommendations
| stage | hours | essentials | comfort |
|---|---|---|---|
| Stage 1-2 | 2-4 hours | 3kWh | 5kWh |
| Stage 3-4 | 4-6 hours | 5kWh | 8-10kWh |
| Stage 5-6 | 6-8 hours | 8kWh | 10-15kWh |
| Stage 7-8 | 8-10 hours | 10kWh | 15-20kWh |
Battery Sizing Tips
Expert recommendations:
- Start with 5kWh minimum - smaller batteries are false economy
- Lithium batteries last 10+ years, lead-acid only 3-5 years
- Buy expandable - most systems allow adding batteries later
- Don't forget overnight: solar doesn't generate at night
- Winter produces 30-40% less solar - size for worst case
Price Disclaimer: Prices shown were verified on . Prices may change without notice. We earn affiliate commissions on qualifying purchases.
All prices are in South African Rand (ZAR) unless otherwise stated. Shipping costs may apply depending on your location.
Related Pages
Battery Sizing Guide FAQs
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